G-QRP Club Limerick Sudden Manual de usuario

The G-QRP Club

The Limerick Sudden 20m Transmier Kit

Circuit design – Ge rge D bbs G3RJV

PCB design – Rex Harper W1REX

Kit – Graham Firth G3MFJ

Manual – G3RJV and G3MFJ

Founded in 1974, the G-QRP Club is the largest QRP Club in the

world. The club e ists to promote interest and growth in low

power amateur radio communication (5 watts or less). Member-

ship is open to any licensed radio amateur or short wave listener

anywhere in the world.

The club publishes a quarterly journal called SPRAT, which is

sent free to members. SPRAT contains many circuits, technical

hints and ideas for QRP construction projects, together with club

news, contest and award information and other items of interest

to QRP operators. SPRAT is an e clusive QRP journal and con-

tains much practical information in each issue. The club operates

a club sales department where components are available at spe-

cial prices to club members. We also publish QRP books which

are available to members.

If you are not a member, and would like to find out more, please

look at www.gqrp.com. For a sample SPRAT and a membership

form, please send your name and address to our membership

secretary:

Daphne Newsum G7ENA, 33 Swallow Drive, Louth, LN11 0DN

membership@gqrp.co.uk

Please mention where you saw this information

Transmier Overview

The Limerick Sudden Transmier is a simple circuit f r a reliable QRP transmier. Alt-

h ugh crystal c ntr lled, the scillat r stage (T1) is a Variable Crystal Oscillat r (VXO).

The crystal supplied is a fundamental frequency crystal n 14.060MHz, the QRP calling

frequency n the 20 metre band, alth ugh ther frequencies are available f r the CW

end f this band. N 4ce that an induct r (L1) and a variable capacit r (VC1) have been

added in series with the crystal and gr und. These induc4ve and capaci4ve elements

all w s me shi6ing f the frequency.

The scillat r utput is c upled via C4 t a 2N3904 Driver stage (T2). TR1 f rms the RF

(radi frequency) l ad f r the stage. It is als a c upling transf rmer t drive the p wer

ampliﬁer. The transf rmer is w und n an FT37-43 c re; a ferrite c re f r br adband

c upling. The primary winding is 25 turns f 30 s.w.g. enameled wire. (G ld) The sec-

ndary winding is 5 turns f the red wire w und ver the centre f the primary winding.

The value f the resistance in the emier f T2 determines the am unt f drive available

t T3 and hence the utput p wer f the transmier. A preset p ten4 meter (VR1) is

placed in series with R6 and acts as a DRIVE c ntr l.

The NPN 2N3906 transist r (T4) is used as a Key Switch t key the transmier. This keys

b th the scillat r and the buﬀer/driver (T1 and T2). In many QRP transmier designs it

is c mm n t leave the scillat r free running and t key later stages. This is because

keying an RF scillat r can result in a “chirpy” CW n te. H wever, T1 is a crystal c n-

tr lled scillat r and n such chirp ccurs. Keying b th stages verc mes the pr blem

f scillat r break-thr ugh when the scillat r is s4ll running in the receive m de.

SW1 is a NET switch that enables the scillat r t run with ut keying the transmier. It

pr vides 12 v lts f r the scillat r and D1 prevents this v ltage reaching T2. This facility

all ws the scillat r t be heard in the receiver s that the VXO signal can be adjusted t

a desired frequency r aligned with a desired sta4 n signal. “NeGng” is standard prac-

4ce when a separate transmier and receiver are being used; it is als called “sp Gng”

in N rth America.

T3 is the transmier p wer ampliﬁer (the Final). This is a simple Class C ampliﬁer biased

by the drive v ltage fr m TR1. The utput l ad is pr vided by L2, an RF ch ke. A zener

di de (ZD1) ﬀers pr tec4 n f r the utput transist r sh uld the transmier be inad-

vertently perated with ut an antenna r int a sh rt circuit. A clip- n heat sink keeps

the transist r c l. C6 c uples the RF utput t a seven element L w-Pass Filter based

n the W3NQN ﬁlter data, with enhanced 2

nd harm nic ﬁltering.

The capacit r C7 leads t the transmier-receiver break-in circuit p pularized by W7EL

in his “Op4mised Transceiver” design. It is a simple meth d f sharing the same anten-

na by a transmier and receiver with ut damage t the receiver during transmissi n r

signiﬁcant l ss f signal fr m the transmier. S me mu4ng f the signal fed t the re-

ceiver is achieved by the circuit T5, T6 and T7. The mu4ng circuit is such that when a

receiver is c nnected t the transmier, 12 v lts must be c nnected t the transmier

t hear signals. The mu4ng is m st eﬀec4ve when the c vers are n the transmier and

receiver.

Building the Transmier

Y u will have n 4ced that this is a rather unusual kit. It has a printed circuit b ard

with ut any h les. We call it “Limerick C nstruc4 n” because it was designed by Rex

Harper, W1REX, f Limerick, Maine. It is a surface m unted b ard in that the c mp -

nents are m unted n the surface f the b ard, alth ugh the c mp nents used are

“thr ugh-h le” parts. This all ws f r ease f c nstruc4 n and easy c rrec4 n f any

err rs. The main b ard als has the fr nt and back panels f r the transmier. They are

sc red and can be snapped ﬀ the main b ard. We suggest y u sm th the snapped

ﬀ edges with emery paper r an emery b ard. The c mp nent parts are s ldered t

the t p surface f the b ard using the leads that w uld g thr ugh the b ard n a

c nven4 nal printed circuit b ard. The interc nnec4 ns between the m un4ng pads

are ready made but hidden by the black screen printed verlay. The designa4 n f all

the parts is printed next t the appr priate pads. Each sec4 n f the transmier

(OSCILLATOR, DRIVER, FINAL, LOW-PASS FILTER and KEY SWITCH) is als marked n

the b ard. The MUTE circuit c mp nents are m unted n the back panel. Any refer-

ences t t p, b m, le4 and right assume that the b ard is held with the printed text

the c rrect way, with the G-QRP Club l g in the centre right. T p is actually the Rear

f the ﬁnished b ard, and b m is, f c urse, the Fr nt.

It d es help t set ut all the c mp nents in the rder

f designa4 n. i.e. C1, C2 etc. The best way is t use a

small piece f p lystyrene t h ld the individual parts.

If y u are g ing t use this idea f r semic nduct rs, a

piece f aluminium f il wrapped r und the p lystyrene

will prevent any sta4c damage. D uble check the ca-

pacit r values—there is a l t f diﬀerence between a

101 and a 104 capacit r!

The building f the transmier d es entail winding f ur

c ils n t r id c res (TR1, and L4, L5 and L6), and an RF

ch ke f r the PA wired n a pig-n sed bin cular c re

(L2). The c res are the small rings that l k like miniature “P l Mints”. L1 and L3 are

pre-w und ch kes (c ils) that l k like fat resist rs. Winding the c ils is n t diﬃcult; it

just requires a lile care and the accurate c un4ng f the number f turns. There is

ample guidance in the pages f this manual. It is a g d idea t wind TR1 bef re begin-

ning t add any ther c mp nents t the b ard. It is the m st diﬃcult f the hand-

w und c ils as it has tw windings, a tuned winding and a smaller link winding.

TR1 is w und n the FT37-43 c re. This is the black c re - the ne with ut the yell w

c a4ng. The primary winding has 25 turns f the g ld wire. There is guide as t h w

t wind these n the next page. Each 4me the wire passes thr ugh the h le f the c re

c unts as ne turn. The turns sh uld be laid side by side and ccupy ab ut three-

quarters f the circumference f the c re. The link winding is 5 turns f the red wire

w und ver the centre f the main winding. Placement f the link winding is n t t

cri4cal – just guess the centre p si4 n.

When the windings have been made, trim the ends f the wires t ab ut 1cm. The wire is

c ated with enamel insula4 n. Ab ut 5mm f each wire sh uld be 4nned with s lder pri r

t making the c nnec4 ns. The enamel c a4ng n the wire supplied is designed t melt

when the s ldering ir n is applied. This d es require quite a bit f heat. The best meth d is

t f rm a bl b f s lder n the s ldering ir n 4p. Apply the 4p t the very end f the wire

and wait un4l the enamel melts and the s lder ﬂ ws nt the c pper wire. This can take up

t 20 sec nds. Then m ve the wire thr ugh the bl b un4l y u get the required 5mm r s

4nned. It’s best n t t breathe in the sm ke given ﬀ during this pr cess.

Winding t r idal c ils is easy. It just requires pa4ence

and care. TR1 uses the black c re with the g ld wire f r

the main winding. The 25 turns require 15” f wire. Each

4me the wire passes thr ugh the

h le (including the ﬁrst 4me) it

c unts as ONE turn. H ld the

c re ﬁrmly with ne hand and

thread the wire thr ugh

with the ther hand, lay-

ing the windings side by

side. Tighten the wire a6er each turn f r a neat c il.

S me4mes if the wire

gets twisted and f rms

a l p it results in a

kink. Untwist the wire carefully. Trying t pull ut the

kink can snap the wire. C mplete the 25 turns. They

sh uld ccupy ab ut three-quarters f the circumfer-

ence. The 5 turn link winding, using red wire, is added

ver the centre f the main winding. Guess the cen-

tre, it is n t really cri4cal

TR1 is m unted ver4cally in the centre f f ur pads. The primary

(larger) winding is s ldered t the t p right pad and the b m

le6 pad. The link (5 turn) winding t the ther tw pads.

The transmier is built in tw sec4 ns; the ﬁrst being the le6-

hand side f the circuit diagram as far as R7. This includes the

OSCILLATOR, the DRIVER and the KEY SWITCH. These are then

tested bef re the rest f the stages are added.

Begin by s ldering the transist rs T1, T2 and T4 t the appr priate pads.

The shape f the transist rs marked n the b ard indicates their rienta-

4 n. They must be placed the c rrect way r und. T enable a secure s l-

der c nnec4 n f the parts, the leads are bent int an “L” shape f r adding

t the pads n the b ard.

Add the resist rs as far as R9 and the capacit rs C1, C3, C4,

C5, C8, C9, C10 and C11. Capacit r C11 is an electr ly4c

capacit r and must be c nnected the c rrect way r und.

The nega4ve lead (marked with a series f dashes – see

drawing) g es t the b m pad f the tw pads designat-

ed f r C11. C8 sh uld be bent t be ﬂat against the b ard as therwise it may f ul the key

jack later. (N te - C2 is n t used in the 20m versi n f this transmier)

When the resist rs and capacit rs are in place, the s cket f r X1 (the

quartz crystal), L1, D1 and RV1 sh uld be added in their appr priate

places. The s cket f r X1 is a 3 way strip and alth ugh we nly use the

uter 2 pins we will c nnect all three pins t the 3 pads n the circuit

b ard. The di de D1 pads have a bar marking t c rresp nd with the

band n the di de. This di de is very similar t ZD1 – y u may need a

magnifying glass t be sure that y u have the c rrect di de.

The fr nt panel

The fr nt panel h lds the variable tuning capacit r (TUNE), the net switch (NET SW) and

the key jack s cket (KEY). These sh uld be ﬁed, and we suggest that the wiring f r these is

added as well. S lder these at the c mp nent ends ﬁrst, we will s lder the main b ard

ends later.

The tuning capacit r

The tuning capacit r is a tw sec4 n p lyvaric n type but nly the

sec4 n with the smallest capacitance is used. There are markings

(rather small) t indicate the capacitance f each sec4 n. A = 140pF,

O = 60pF and G = Gr und. We nly require the O and G c nnec4 ns.

The “A” s lder tag can be cut sh rt (but n t rem ved) t av id c n-

fusi n. 2 ﬀ 3cm lengths f wire (yell w (O) and black (G)) f r the

tuning capacit r sh uld be s ldered n the capacit r.

The tuning capacit r is m unted t the fr nt panel using the tw

small screws pr vided. It is m unted tags d wnward.

The key jack s cket

The s cket is a 3.5mm s cket t be used with a 3.5mm m n

jack plug s ne f the c nnec4 ns, (which is a switch c n-

tact), is unused. It is a g d idea t cut ﬀ the unwanted s l-

der tag t av id c nfusi n. The gr und tag sh uld be t the

uter edge. The wires f r this will be s ldered t the main

b ard ﬁrst, and c nnected t the jack a6er the panel is ﬁed.

The NET switch

NET SW is a small t ggle switch that requires tw wires

t be j ined t the SW1 pads n the main b ard. Which

wire g es t which pad is n t imp rtant as this is a sim-

ple n/ ﬀ switch. Use the t p tw c ntacts n the

switch f r the wires. When the switch lever is p in4ng

d wnwards a c nnec4 n is made between these tw c ntacts. The n rmal p si4 n f the lever

when using the transmier is upwards. 2 pieces f wire (blue and range, 10 cm l ng) sh uld be

s ldered t the net switch, and then twisted t gether ver their full length. N rth American

builders wh seem t like their switches upside d wn c mpared t Eur pean switches may wish

t use this switch with VFO n being up!

N w, the LED (light emiGng di de) can be m unted n the fr nt

panel. This ﬁts int a small h le marked “SIG” f r signal because the

di de t there t gl w whenever a signal is being transmied.

On the inside f the fr nt panel, either side f the SIG h le, there is a d uble pad and a single

pad. The nega4ve side (-) f the LED is c nnected t gr und at the single pad. The p si4ve side

f the LED is c nnected t the d uble pad nearest the h le. The uter pad, marked “LED” is

c nnected with a wire t the LED pads t the right f R10 n the main b ard. The l ngest lead

f the LED is the p si4ve lead. T m unt the LED, push it int the SIG h le and, using p inted

pliers, gently bend the leads in an arc t reach the desired pads.

The ﬁnished fr nt panel sh uld l k like this –

N w rem ve the insula4 n c mpletely fr m tw 2cm

pieces f the black wire, and s lder ne end f each

piece f bare wire t the KEY pads n the main b ard. Be

careful y u d n’t catch y ur ﬁngers n these when they

are stuck up in the air!

Add the side cheeks

This is a g d 4me t s lder the “side

cheeks” int place either side f the main

b ard. These are designed as ﬁxing plate f r

the encl sure. Adding the side cheeks at

this p int d es mean that the ﬁxing f the fr nt and back panels f the receiver is much

easier. Aaching the side cheeks d es require a really h t s ldering ir n bit and plenty f

s lder. These are n t iden4cal s make sure y u have the right nes at the c rrect sides –

see the picture bel w t check. We sh uld, at this p int, rec mmend ur SBSS clamps,

which are designed f r this purp se - b th the side cheeks, and the fr nt panel are easily

ﬁxed this way.

If y u d n’t use ur clamps, then we suggest that y u begin with a large bl b f s lder at

ne end t ﬁx the p si4 n. Aempt t get the side cheek as near ver4cal as p ssible and

exactly in line with the main b ard. When y u are happy with this, y u sh uld put a few

bl bs f s lder n the narr w pads n the length f the b ard. Be careful near the blue

variable resist r, the plas4c easily melts when t uched by the ir n!

When y u have ﬁed these, the fr nt panel can be

s ldered in place – a6er c nnec4ng the variable capaci-

t r and net switch leads. The O (yell w) g es t the le6-

hand pad nearest t the centre f the fr nt f the

b ard, and the G c nnec4 n (black) g es t the right-

hand (nearer the edge) pad.

This picture sh ws that d ne, and the c rrect way

r und f the side panels alth ugh they have n t been

s ldered int place yet.

Like the side cheeks the fr nt panel is s ldered

t the main b ard. This panel, unlike the side

cheeks, verlaps the base b ard. The base

b ard sh uld be put in the gap between the

s ldered tracks at the b m f the fr nt pan-

el. This picture sh ws the c rrect p si4 n f

the fr nt panel against the base. Again, we

suggest that y u use the “ ne bl b” technique

underneath the b ard t get the panel aligned

c rrectly and ver4cal. Add a sec nd bl b when

y u are happy with the alignment, then y u

sh uld put a

few g d bl bs f s lder al ng the t p side f the b ard

f r extra strength.

Finally f r this stage, c nnect the tw bare wires t the key

jack – this picture sh ws that d ne. The gr und c nnec4 n

(see diagram—t p f page 7) sh uld be nearest the side f

the case

C mplete circuit

diagram

Tes9ng the ﬁrst sec9 n

Tes4ng the transmier at this stage

requires a Di de Pr be. All the parts

are pr vided f r making such a pr be as

sh wn in the picture.

The di de pr be is built “Manhaan-

style” by aaching a strip f ﬁve pads t

the t p le6-hand c rner f the printed

circuit b ard material using super glue.

The c mp nents are surface m unted as sh wn. The three le6-hand pads are j ined using

an ﬀ-cut fr m ne f the trimmed c mp nent leads.

Flexible wire in red, black, yell w and green is supplied. The yell w and green leads are

terminated with cr c dile clips and the red and black leads are terminated with 4mm plugs

(the standard plug used in test meters). If y ur meter uses a diﬀerent size f plug, then y u

will have t btain these y urself. The placement f the f ur leads is sh wn in the circuit

drawing. Later the di de pr be will be c nverted int a basic wameter t measure the ﬁnal

transmier utput.

F r th se n t familiar with 4mm plugs, the centre f the metal insert c ntains a grub screw

t secure the end f the wire. A small screw driver pushed up the centre f the metal insert

is used t clamp the end f the wire as sh wn. The metal insert is then pushed int the plas-

4c h using f the plug, wire being place in line with the sl t in the plas4c h using. The insert

is n w pushed un4l the end f the plug is as far ut as it will travel. This d es take f rce!

Pushing the end f the insert against a ﬁrm surface will help. Y u might need a screwdriver

t push in the ﬁnal bit f the metal insert.

Otros manuales para Limerick Sudden

Otros manuales de Transmisor de G-QRP Club

G-QRP Club

G-QRP Club Limerick Sudden Manual de usuario

Manuales populares de Transmisor de otras marcas

NIVELCO

NIVELCO EasyTREK SCA-300 Series Manual del propietario

Honeywell

Honeywell 5816WMBR Manual de usuario

Kamstrup

Kamstrup READy MTU Instrucciones de funcionamiento

Omega

Omega ZW Series Manual de usuario

ABB

ABB Field 264H Guía

Alinco

Alinco DJ-V17T Manual de usuario

Dejero

Dejero EnGo 3x Manual de usuario

Rosemount

Rosemount 4600 Manual de usuario

Speaka Professional

Speaka Professional 2342740 Manual de usuario

trubomat

trubomat GAB 1000 Manual de usuario

Teledyne Analytical Instruments

Teledyne Analytical Instruments LXT-380 Manual de usuario

Rondish

Rondish UT-11 Manual de usuario

MG 10JRE Manual de usuario

Burkert

Burkert 8177 Manual de usuario

Firetide

Firetide HotPort 3203 Manual

Tele Radio

Tele Radio T9-02 Manual de usuario

Rotronic

Rotronic HygroFlex HF3 Series Manual de usuario

Jamara

Jamara FCX6 Pro Tel Manual de usuario